The invention relates to a method of and to a plant for regulating the temperature of water, oil or another suitable heat carrier fluid. More particularly, the invention relates to improvements in a method of and in a plant for regulating the temperature of a heated or cooled fluid which flows from a heat influencing unit (e.g., a furnace) to one or more heat exchangers, preferably in one or more spaces which are, or which can be, at least substantially sealed from the surrounding atmosphere.
It is customary to regulate the temperature of a fluid (e.g., water) which flows from a heating unit (such as an air cooler or a furnace) to one or more heat exchangers (such as radiators which are set up in the rooms of a dwelling or a commercial establishment to cool or heat the air in the room or rooms) in dependency on changes of the outside temperature. As a rule, the regulating operation is carried out in such a way that the cooling action or the heat output of the plant conforms to the continuously or intermittently varying gradient between room temperature and outside temperature. A drawback of such plants is that they do not take into consideration the heat storing or accumulating capacity of walls which surround the heated room or rooms. Consequently, an abrupt drop of outside temperature after a longer period of warm weather entails an abrupt increase of the heat output of the furnace in such a plant even though the amount of heat which is stored in the walls would have permitted a relatively short or even an extended delay of an increase of the heat output. Inversely, when the outside temperature rises abruptly after a prolonged cold spell and the temperature rise is substantial, the heat output of the furnace is likely to be reduced prematurely even though the walls are still cold or cool because they are being heated at a rate which is much slower than that of heating of the outside air.
Attempts to overcome the aforediscussed drawbacks of conventional plants include the installation of temperature sensors which are embedded in or otherwise implanted in the walls. This does not solve the problem because such sensors are incapable of adequately monitoring the temperature of an entire wall, i.e., their signals are merely indicative of the wall temperature in their immediate or close proximity. Therefore, the results of measurements which are carried out by such sensors are often misleading and cannot contribute to a pronounced improvement in the heating action of conventional plants.
A further serious drawback of conventional plants is that they are invariably overtaxed if they are to be operated by taking into consideration other variables, such as internal loads in a building complex and the like. The internal loads can include intentional ventilation of rooms by opening the windows or by starting electric fans or other air circulating means as well as the delivery of heat energy, for example, by a large number of persons or in other ways of raising the temperature of confined air. In such instances, a conventional plant must be equipped with additional bulky, complex and expensive controlling and regulating apparatus in order to reduce the likelihood of excessive heat losses or the admission of excessive quantities of heat.